1. Field of Invention
The present invention relates to an alarm system, and more particularly to an alarm system with digital verification control, which can optimize both the false alarm reduction performance and the security protection performance.
2. Description of Related Arts
It is reported that less than 5% of the triggered alarms are caused by actual illegal events. More than 90% of the triggered alarms are false alarms caused by the detection as PIRs sensors. False alarms are the unsolved troubles to both the alarm companies and the police resources. Most alarm system owners have the unpleasant experience of being awaken in mid-night by the alarm company due to false alarms. Moreover, unaccountable waste of time and police force have been suffered by most of the policemen. Before the policemen arrive at the scene, no one knows whether it is a false alarm or an actual alarm. Therefore, the local police resource charges the alarm system owner a pretty high amount for a false alarm operation fee for each false alarm which causes a lot of complaints from users also. It creates a great burden to the limited police force in every city. In fact, millions of expenses have been wasted for the police resources in responding to the false alarms, that greatly degrades the efficiency and performance of the police. Accordingly, some of the police stations in this country consider abandoning such alarm response service. It will only be good news to all burglars. Therefore, how to effectively minimize the possibility of false alarm becomes an urgent topic to both the alarm users and the police resources.
The triggering of false alarms may frequently be caused by the insects such as the spiders and cockroach entering the covering area of a PIR sensor, the activity of animals such as birds, rats, and pets inside the PIR sensor covering area, and the vehicle headlight and weather thunder. It is because the detection ability of PIR sensor does not contain any verification capability like the human beings.
According to statistics, there are approximately 32.3 million to 35.5 million false alarm activations per year. The vast majority of alarm calls, between 94-98%, are false and approximately US$1.3 billion in annual costs are due to false alarms. In fact, reliability of alarms, if measured using false alarm rates, is generally between 2-6% only.
False alarms account for 10-25% of all calls to police. Each false alarm requires approximately 20 minutes of police time of usually two officers. Currently, between 21 and 24 million security alarm systems are in the US and approximately 18 million of which are monitored. One out of every seven U.S. businesses and one of every nine U.S. residences have alarms. Some industry estimates suggest that 1.5 million new alarms are installed annually. Solving the problem of false alarms would relieve 35,000 officers from providing what many sees as an essentially private service.
A process and system for reducing motion-type false alarm of security alarm system patented by the applicant of the present invention, U.S. Pat. Nos. 5,917,409, 6,166,633 and 6,157,299, seems to be the only solution today wherein the alarm system provides a verification condition to delay the activation of the control plane so as to reduce the false alarm possibility. The verification process is performed when one of the motion sensors detects a trigger motion within a respective motion detecting area, a motion signal is delayed for a preset time period as a single zone delaying period to send to the control panel. Therefore, the control panel is activated to normally respond by activating the local warning system to produce warning signals when the same motion sensor that detected the trigger motion detects another motion in the same motion detecting area within the single zone delaying period. Statistically, between year 2000 and 2002 when the alarm system incorporates with the verification process, the total false alarm reports were significantly reduced to 2% in comparison with the alarm system without the verification process.
However, since each building has its own interior structure, the single zone delaying period for each PIR sensor must be preset correspondingly. When the PIR sensor has a shorter single zone reacting period, the false alarm possibility will be reduced. However, the security protection of the alarm system will also be reduced.
In addition, when multiple zones are involved in the alarm system, another PIR sensor is preset as a cross zone reacting period. However, the time frame of the cross zone reacting period is an unknown to optimize both the false alarm reduction and the security protection.
The cross setting of the single zone and multiple zone raises a problem to the verification process. The conventional time zone setting for the multiple zone alarm system is that the cross zone reacting period is set as same as the single zone reacting period. However, it is not effective and generally fails to achieve the best performance.